Serena Williams is 27 today. Others celebrating: Music exec Andre Harrell is 48, Christina Milian is 27, former New Jersey governor Christine Todd Whitman is 62, Olivia Newton-John is 60, and Linda Hamilton turns 52. Two figures on the New York web scene will be blowing out candles this evening: Gothamist co-founder Jen Chung is 32. And Nerve.com founder Rufus Griscom is 41. Weekend birthdays after the jump!